(華南理工大學(xué) 機械工程學(xué)院，廣州 510640)
摘 要: 采用SEM、TEM、EDX、XRD、AUTOLAB電化學(xué)工作站分析比較兩種電解質(zhì)(硅酸鹽體系和有機胺體系)直流微弧氧化處理AZ91D合金表面涂層的成分、組織結(jié)構(gòu)和涂層的動電位極化曲線。雖然兩種電解質(zhì)體系涂層元素成分和組成相相同，均為金屬相、MgO相和Mg2SiO3相，但有機胺電解質(zhì)體系的涂層中非金屬相(MgO、Mg2SiO4)相對含量高于硅酸鹽處理體系，有機胺體系獲得的涂層表面均勻致密性也優(yōu)于硅酸鹽體系。有機胺體系獲得的涂層在3.5% NaCl中性介質(zhì)中的腐蝕電流密度、腐蝕電壓分別為0.29 mA/cm2 和522 mV，與硅酸鹽體系處理涂層相比，前者的抗腐蝕能力有很大幅度的提高。
關(guān)鍵字: 鎂合金；微弧氧化；電解質(zhì)；有機胺；腐蝕
（College of Mechanical Engineering, South China University of Technology, Guangzhou 510640, China）
Abstract:Abstract: By means of SEM, TEM, EDX, XRD and AUTOLAB, the composition, constituent phase, microstructure and corrosion resistance of two micro-arc coatings were investigated, which were treated in two electrolytes: organic amine system and silicate solution. The results show that the constituent phases in coatings from two electrolyte are the same, i.e., α/β-Mg, MgO and Mg2SiO4; the relative fraction of ceramic phases in the coating from organic amine is higher, and the coating surface morphology looks finer and denser than those from silicate solution. According to the potential-dynamic polarization curves in 3.5% NaCl solution, the corrosion current density and corrosion voltage from organic amine treated coating are 0.29 mA/cm2 and 522 mV respectively. The corrosion resistance of organic amine treated coating is improved significantly.
Key words: magnesium alloy; micro-arc oxidation; electrolyte; organic amine; corrosion
